LCOV - code coverage report
Current view: top level - libdw - dwarf_getalt.c (source / functions) Hit Total Coverage
Test: elfutils-0.190 Lines: 62 67 92.5 %
Date: 2023-11-21 13:31:15 Functions: 3 3 100.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 35 58 60.3 %

           Branch data     Line data    Source code
       1                 :            : /* Retrieves the DWARF descriptor for debugaltlink data.
       2                 :            :    Copyright (C) 2014, 2018 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            : 
       5                 :            :    This file is free software; you can redistribute it and/or modify
       6                 :            :    it under the terms of either
       7                 :            : 
       8                 :            :      * the GNU Lesser General Public License as published by the Free
       9                 :            :        Software Foundation; either version 3 of the License, or (at
      10                 :            :        your option) any later version
      11                 :            : 
      12                 :            :    or
      13                 :            : 
      14                 :            :      * the GNU General Public License as published by the Free
      15                 :            :        Software Foundation; either version 2 of the License, or (at
      16                 :            :        your option) any later version
      17                 :            : 
      18                 :            :    or both in parallel, as here.
      19                 :            : 
      20                 :            :    elfutils is distributed in the hope that it will be useful, but
      21                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23                 :            :    General Public License for more details.
      24                 :            : 
      25                 :            :    You should have received copies of the GNU General Public License and
      26                 :            :    the GNU Lesser General Public License along with this program.  If
      27                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      28                 :            : 
      29                 :            : #ifdef HAVE_CONFIG_H
      30                 :            : # include <config.h>
      31                 :            : #endif
      32                 :            : 
      33                 :            : #include "libdwP.h"
      34                 :            : #include "libelfP.h"
      35                 :            : #include "libdwelfP.h"
      36                 :            : #include "system.h"
      37                 :            : 
      38                 :            : #include <inttypes.h>
      39                 :            : #include <fcntl.h>
      40                 :            : #include <limits.h>
      41                 :            : #include <stdlib.h>
      42                 :            : #include <stdio.h>
      43                 :            : #include <string.h>
      44                 :            : #include <sys/types.h>
      45                 :            : #include <sys/stat.h>
      46                 :            : 
      47                 :            : 
      48                 :            : char *
      49                 :            : internal_function
      50                 :        144 : __libdw_filepath (const char *debugdir, const char *dir, const char *file)
      51                 :            : {
      52         [ -  + ]:        144 :   if (file == NULL)
      53                 :            :     return NULL;
      54                 :            : 
      55         [ -  + ]:        144 :   if (file[0] == '/')
      56                 :          0 :     return strdup (file);
      57                 :            : 
      58   [ +  +  +  - ]:        144 :   if (dir != NULL && dir[0] == '/')
      59                 :            :     {
      60                 :          2 :       size_t dirlen = strlen (dir);
      61                 :          2 :       size_t filelen = strlen (file);
      62                 :          2 :       size_t len = dirlen + 1 + filelen + 1;
      63                 :          2 :       char *path = malloc (len);
      64         [ +  - ]:          2 :       if (path != NULL)
      65                 :            :         {
      66         [ +  - ]:          2 :           char *c = mempcpy (path, dir, dirlen);
      67         [ +  - ]:          2 :           if (dir[dirlen - 1] != '/')
      68                 :          2 :             *c++ = '/';
      69                 :          2 :           mempcpy (c, file, filelen + 1);
      70                 :            :         }
      71                 :          2 :       return path;
      72                 :            :     }
      73                 :            : 
      74         [ +  + ]:        142 :   if (debugdir != NULL)
      75                 :            :     {
      76                 :        102 :       size_t debugdirlen = strlen (debugdir);
      77         [ -  + ]:        102 :       size_t dirlen = dir != NULL ? strlen (dir) : 0;
      78                 :        102 :       size_t filelen = strlen (file);
      79                 :        102 :       size_t len = debugdirlen + 1 + dirlen + 1 + filelen + 1;
      80                 :        102 :       char *path = malloc (len);
      81         [ -  + ]:        102 :       if (path != NULL)
      82                 :            :         {
      83         [ -  + ]:        102 :           char *c = mempcpy (path, debugdir, debugdirlen);
      84         [ -  + ]:        102 :           if (dirlen > 0)
      85                 :            :             {
      86         [ #  # ]:          0 :               c = mempcpy (c, dir, dirlen);
      87         [ #  # ]:          0 :               if (dir[dirlen - 1] != '/')
      88                 :          0 :                 *c++ = '/';
      89                 :            :             }
      90                 :        102 :           mempcpy (c, file, filelen + 1);
      91                 :        102 :           return path;
      92                 :            :         }
      93                 :            :     }
      94                 :            : 
      95                 :            :   return NULL;
      96                 :            : }
      97                 :            : 
      98                 :            : static void
      99                 :         82 : find_debug_altlink (Dwarf *dbg)
     100                 :            : {
     101                 :         82 :   const char *altname;
     102                 :         82 :   const void *build_id;
     103                 :         82 :   ssize_t build_id_len = INTUSE(dwelf_dwarf_gnu_debugaltlink) (dbg,
     104                 :            :                                                                &altname,
     105                 :            :                                                                &build_id);
     106                 :            : 
     107                 :            :   /* Couldn't even get the debugaltlink.  It probably doesn't exist.  */
     108         [ +  + ]:         82 :   if (build_id_len <= 0)
     109                 :         38 :     return;
     110                 :            : 
     111                 :         44 :   const uint8_t *id = (const uint8_t *) build_id;
     112                 :         44 :   size_t id_len = build_id_len;
     113                 :         44 :   int fd = -1;
     114                 :            : 
     115                 :            :   /* We only look in the standard path.  And relative to the dbg file.  */
     116                 :            : #define DEBUGINFO_PATH "/usr/lib/debug"
     117                 :            : 
     118                 :            :   /* We don't handle very short or really large build-ids.  We need at
     119                 :            :      at least 3 and allow for up to 64 (normally ids are 20 long).  */
     120                 :            : #define MIN_BUILD_ID_BYTES 3
     121                 :            : #define MAX_BUILD_ID_BYTES 64
     122         [ +  - ]:         44 :   if (id_len >= MIN_BUILD_ID_BYTES && id_len <= MAX_BUILD_ID_BYTES)
     123                 :            :     {
     124                 :            :       /* Note sizeof a string literal includes the trailing zero.  */
     125                 :         44 :       char id_path[sizeof DEBUGINFO_PATH - 1 + sizeof "/.build-id/" - 1
     126                 :            :                    + 2 + 1 + (MAX_BUILD_ID_BYTES - 1) * 2 + sizeof ".debug"];
     127                 :         44 :       sprintf (&id_path[0], "%s%s", DEBUGINFO_PATH, "/.build-id/");
     128                 :         44 :       sprintf (&id_path[sizeof DEBUGINFO_PATH - 1 + sizeof "/.build-id/" - 1],
     129                 :         44 :                "%02" PRIx8 "/", (uint8_t) id[0]);
     130         [ +  + ]:        880 :       for (size_t i = 1; i < id_len; ++i)
     131                 :        836 :         sprintf (&id_path[sizeof DEBUGINFO_PATH - 1 + sizeof "/.build-id/" - 1
     132                 :        836 :                           + 3 + (i - 1) * 2], "%02" PRIx8, (uint8_t) id[i]);
     133                 :         88 :       strcpy (&id_path[sizeof DEBUGINFO_PATH - 1 + sizeof "/.build-id/" - 1
     134                 :         44 :                        + 3 + (id_len - 1) * 2], ".debug");
     135                 :            : 
     136   [ +  -  -  + ]:         44 :       fd = TEMP_FAILURE_RETRY (open (id_path, O_RDONLY));
     137                 :            :     }
     138                 :            : 
     139                 :            :   /* Fall back on (possible relative) alt file path.  */
     140         [ +  - ]:         44 :   if (fd < 0)
     141                 :            :     {
     142                 :         44 :       char *altpath = __libdw_filepath (dbg->debugdir, NULL, altname);
     143         [ +  + ]:         44 :       if (altpath != NULL)
     144                 :            :         {
     145   [ -  +  -  - ]:          4 :           fd = TEMP_FAILURE_RETRY (open (altpath, O_RDONLY));
     146                 :          4 :           free (altpath);
     147                 :            :         }
     148                 :            :     }
     149                 :            : 
     150         [ +  + ]:         44 :   if (fd >= 0)
     151                 :            :     {
     152                 :          4 :       Dwarf *alt = dwarf_begin (fd, O_RDONLY);
     153         [ +  - ]:          4 :       if (alt != NULL)
     154                 :            :         {
     155                 :          4 :           dbg->alt_dwarf = alt;
     156                 :          4 :           dbg->alt_fd = fd;
     157                 :            :         }
     158                 :            :       else
     159                 :          0 :         close (fd);
     160                 :            :     }
     161                 :            : }
     162                 :            : 
     163                 :            : Dwarf *
     164                 :        642 : dwarf_getalt (Dwarf *main)
     165                 :            : {
     166                 :            :   /* Only try once.  */
     167   [ +  -  +  + ]:        642 :   if (main == NULL || main->alt_dwarf == (void *) -1)
     168                 :            :     return NULL;
     169                 :            : 
     170         [ +  + ]:        346 :   if (main->alt_dwarf != NULL)
     171                 :            :     return main->alt_dwarf;
     172                 :            : 
     173                 :         82 :   find_debug_altlink (main);
     174                 :            : 
     175                 :            :   /* If we found nothing, make sure we don't try again.  */
     176         [ +  + ]:         82 :   if (main->alt_dwarf == NULL)
     177                 :            :     {
     178                 :         78 :       main->alt_dwarf = (void *) -1;
     179                 :         78 :       return NULL;
     180                 :            :     }
     181                 :            : 
     182                 :            :   return main->alt_dwarf;
     183                 :            : }
     184                 :            : INTDEF (dwarf_getalt)

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